Questions and answers on iron deficiency treatment selection and the use of intravenous iron in routine clinical practice

Abstract

Iron deficiency is a common cause of morbidity and can arise as a consequence or complication from many diseases. The use of intravenous iron has increased significantly in the last decade, but concerns remain about indications and administration. Modern intravenous iron preparations can facilitate rapid iron repletion in one or two doses, both for absolute iron deficiency and, in the presence of inflammation, functional iron deficiency, where oral iron therapy is ineffective or has not worked. A multidisciplinary team of experts experienced in iron deficiency undertook a consensus review to support healthcare professionals with practical advice on managing iron deficiency in gastrointestinal, renal and cardiac disease, as well as; pregnancy, heavy menstrual bleeding, and surgery. We explain how intravenous iron may work where oral iron has not. We provide context on how and when intravenous iron should be administered, and informed opinion on potential benefits balanced with potential side-effects. We propose how intravenous iron side-effects can be anticipated in terms of what they may be and when they may occur. The aim of this consensus is to provide a practical basis for educating and preparing staff and patients on when and how iron infusions can be administered safely and efficiently. Key messages Iron deficiency treatment selection is driven by several factors, including the presence of inflammation, the time available for iron replenishment, and the anticipated risk of side-effects or intolerance. Intravenous iron preparations are indicated for the treatment of iron deficiency when oral preparations are ineffective or cannot be used, and therefore have applicability in a wide range of clinical contexts, including chronic inflammatory conditions, perioperative settings, and disorders associated with chronic blood loss. Adverse events occurring with intravenous iron can be anticipated according to when they typically occur, which provides a basis for educating and preparing staff and patients on how iron infusions can be administered safely and efficiently.

Keywords: Anaemia; cardiovascular diseases; chronic; erythrocyte transfusion; inflammatory bowel diseases; infusions; intravenous; iron; iron-deficiency; menorrhagia; pregnancy complications; renal insufficiency.

Figure 1.

The mechanism of oral and intravenous iron treatments. Iron administered via an oral iron supplement is absorbed by duodenal enterocytes. Divalent metal transporter 1 (DMT1) imports iron across the apical surface of enterocytes, whereas ferroportin exports iron across the basolateral surface. The hormone hepcidin, which is increased by iron loading or inflammation, impairs cellular iron export into blood by causing ferroportin degradation. Intravenous iron preparations are administered by infusion, and the iron‒carbohydrate complex is taken up and processed by macrophages in the liver, spleen and marrow. Once iron is released into the cytoplasm, it is either stored in ferritin or exported from macrophages through ferroportin (FPN). Intravenous iron can overcome the hepcidin-mediated block of iron absorption from the gut.

Figure 2.

Adverse events associated with the administration of intravenous iron. Adverse events occurring with intravenous iron can be anticipated according to when they typically occur. Educational material and institutional training should prepare patients and staff for their occurrence, minimizing the need to unnecessarily withhold or abandon administration and reducing the need for subsequent patient visits.